Fig. 2: Protein-nanowire devices and memristive switching.
a Schematic of the planar device structure. b Representative I-V curves from a device. The red curves show a complete sweep loop from 0→150 mV →0 →-150 mV →0. c Switching I–V curves from a device with the current compliance (ICC) set from 10 µA to 1 nA. d Pulsed measurements in a device (N = 32). Same pulses (100 mV, 20 ms; blue curve) were applied to the device with the current (black curves) measured. The conduction state in the device was continuously monitored after the pulse by using a 10 mV reading voltage. e Photo image of 4 vertical protein-nanowire devices with varying sizes of 20 × 20, 10 × 10, 5 × 5, and 2 × 2 µm2. Scale bar 50 µm. The schematic shows the layered Ag–SiO2–Pt (100–25–30 nm thick) device structure embedded in patterned protein-nanowire film (~500 nm thick). f A continuous 800 I–V sweeps in a vertical protein-nanowire device. Above measurements were done in the ambient environment with RH~35%. g Statistics of the turn-on voltage from 57 vertical devices, with an average value of 58 ± 10 mV (± s.d.). h A 104 cycles from a vertical device. Each cycle involved a pulse wave form (inset) consisting of a programming (set) pulse (100 mV, 40 ms), a read pulse (10 mV, 19 ms) of the On current, a reset pulse (−50 mV, 20 ms) to facilitate the relaxation, and a read pulse (10 mV, 19 ms) of the Off current. Current compliance was applied to the On read current with a load resistor. The Off read current was at the instrument noise level (<100 nA) for the measurement range used.
